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Fukushima Unit 2 Refueling Floor Work Poses Risks

Work has begun on the unit 2 refueling floor at Fukushima Daiichi. Previously, TEPCO installed a controlled building on the side of unit 2. This building provides filtered ventilation and a staging area. It will allow workers to send equipment into the reactor building refueling floor. The wall between the two buildings was opened earlier this spring.
After the initial disaster it that unit 2 was creating the most significant radiation releases to the environment.  The highest of the three units that melted down. In 2012 an obvious steam leak from the reactor well was discovered via TEPCO images.
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TEPCO eventually put a filtration system on the building. This prevented radiation releases to the environment. The future plans for this unit include removing the entire refueling floor level. The roof and walls down to the refueling floor deck are to be removed. Then a new cover building with replacement systems will be installed. Workers are still unable to enter the refueling floor area. High radiation levels prevent human entry. Only robots have entered. TEPCO has not addressed this radiation risk during the demolition and construction phase. Earlier reporting mentioned the planned use of dust suppressants during the demolition work. There is no management plan for potential radiation releases from the reactor well.
TEPCO’s schedule shows they may begin removing equipment from inside unit 2’s refueling floor as early as mid-July. The building demolition and spent fuel removal schedule is still somewhat vague. This is dependent on other work completion.
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August 1, 2018 Posted by | Fukushima 2018 | , , , | Leave a comment

Reuse of radioactive soil feared to trigger illegal dumping

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Piles of black bags containing radioactive soil are seen at a temporary storage site in Minamisoma, Fukushima Prefecture, on June 11, 2016. The Environment Ministry is set to conduct a demonstration experiment there possibly later this year, in which radiation doses will be measured on mounds using soil generated from decontamination work.

Reuse of radioactive soil feared to trigger illegal dumping

An Environment Ministry decision to allow reuse of radioactively contaminated soil emanating from the Fukushima nuclear disaster in public works projects has prompted experts to warn against possible dumping of such soil under fake recycling.

The ministry formally decided on June 30 to allow limited use of soil generated from decontamination work after the Fukushima No. 1 nuclear power plant disaster in mounds under road pavements and other public works projects, as long as the soil contains no more than 8,000 becquerels per kilogram of radioactive cesium. The decision was made despite questions raised during a closed meeting of the ministry over incompatibility with the decontamination criteria for farmland soil.

The Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors sets the safety criteria for recycling metals and other materials generated from the decommissioning of nuclear reactors at no more than 100 becquerels per kilogram, and requires materials whose radiation levels exceed that level to be buried underground as “radioactive waste.” The figure of 100 becquerels is derived from the International Commission on Radiological Protection’s standards that annual radiation exposure of up to 0.01 millisieverts poses negligible health risks.

However, the Fukushima disaster has disseminated radioactive materials outside the crippled nuclear plant across far wider areas than expected. Under the special measures law on decontamination of radioactive materials, which was fully put into force in January 2012, waste whose radiation levels top 8,000 becquerels per kilogram is called “designated waste” and must be treated by the government, while waste with radiation levels of 8,000 becquerels or lower can be treated in the same way as regular waste. The figure of 8,000 becquerels comes from the upper limit of annual radiation exposure doses for ordinary citizens under the reactor regulation law, which is set at 1 millisievert. Regarding the double safety standards of 100 becquerels and 8,000 becquerels, the Environment Ministry had earlier explained that the former is for “reuse” and the latter for “waste disposal.”

However, the recent Environment Ministry decision to allow the reuse of contaminated soil in public works projects runs counter to its earlier explanation. The ministry is trying to reconcile that difference by insisting that the radiation levels of tainted soil could be kept under 100 becquerels if mounds using such soil were covered with concrete and other materials to shield radiation. During a closed meeting of the ministry that discussed the matter, some attendants raised questions over inconsistencies with the decontamination criteria for farmland soil.

In April 2011, in the aftermath of the Fukushima meltdowns, the Ministry of Agriculture, Forestry and Fisheries restricted rice planting in paddies whose radiation levels topped 5,000 becquerels per kilogram of soil. While the restriction was effective for just one year, the same criteria has been in place for ensuing decontamination, where surface soil of more than 5,000 becquerels is removed and surface soil under that level is replaced with deeper layers.

It is inconsistent to strip away soil of more than 5,000 becquerels while recycling soil with the same level of radiation. However, attendants of the closed meeting never discussed the matter in detail, nor did the issue come up for discussion at an open meeting.

The radioactivity concentration of contaminated soil is higher than that of earthquake debris, whose treatment caused friction across the country on the heels of the Fukushima crisis. Therefore, officials attending an open meeting of the ministry discussed the introduction of incentives for users of tainted soil, with one saying, “Unless there are motives for using such soil, regular soil would be used instead.”

Kazuki Kumamoto, professor at Meiji Gakuin University specializing in environmental policy, criticized the ministry’s move, saying, “There is a high risk for inverse onerous contracts, in which dealers take on contaminated soil in exchange for financial benefits.” There have been a series of incidents involving such contracts, in which waste was pressed upon dealers under the guise of “recycled materials,” such as backfill material called ferrosilt and slag generated from iron refining.

“If contaminated soil was handed over under inverse onerous contracts, there is a risk that such soil could be illegally dumped later. Reuse of tainted soil would lead to dispersing contamination,” Kumamoto said.

http://mainichi.jp/english/articles/20160705/p2a/00m/0na/012000c

July 5, 2016 Posted by | Fukushima 2016 | , , , | Leave a comment

Ministry green-lights reuse of radioactive soil for public works projects

The Ministry of the Environment formally decided on June 30 to allow limited use of radioactively contaminated soil in public works projects, but sidestepped estimates from a closed-door meeting that the soil may have to be monitored for up to 170 years.

The ministry decided that soil could be reused for embankments as long as the radioactivity of cesium it contained did not exceed 8,000 becquerels per kilogram. Under the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors, contaminated soil can be used freely if the level of radioactivity is 100 becquerels per kilogram or less.

It earlier emerged that the ministry calculated in a closed-door meeting that some soil would have to be monitored for 170 years — well beyond the life of embankments. However, in its basic policy the ministry simply stated, “Safety and administration methods will be examined during verification processes in the future.”

It is expected that up to around 22 million cubic meters of waste contaminated with radioactive material from the Fukushima nuclear disaster will end up piled up at an interim storage facility straddling the border between the Fukushima Prefecture towns of Okuma and Futaba. The central government plans to dispose of the waste for good outside the prefecture by March 2045, but hopes to reuse as much of it as possible to reduce the amount.

Under the ministry’s basic policy, reuse of the soil will be limited to public works where the body in charge of administering it is clearly established, and the radiation dose at a distance of 1 meter is no more than 0.01 millisieverts per year. When using contaminated soil with a level of radioactivity of 8,000 becquerels per kilogram, it would be placed under at least 50 centimeters of cover soil, which would then be covered with sand and asphalt.

During the closed-door meeting, it was calculated that it would take 170 years for the radioactivity of tainted soil to naturally decrease from 5,000 to 100 becquerels per kilogram — much longer than the durability of soil mounds, at 70 years.

http://mainichi.jp/english/articles/20160701/p2a/00m/0na/006000c

July 1, 2016 Posted by | Fukushima 2016 | , , , | Leave a comment

Japan approves guidelines of reusing soil from Fukushima for public works

TOKYO, June 30 (Xinhua) — Japan’s Ministry of the Environment approved Thursday guidelines of reusing contaminated soil from the Fukushima nuclear disaster for national public works despite public concerns over safety.

According to the guidelines, Japan would allow tainted soil generated from the Fukushima decontamination work with the radioactive cesium level lower than a certain limit varying from 5,000 to 8,000 becquerels per kilogram according to different uses, to be reused in national public works.

The tainted soil, while reused, shall be covered with clean earth, concrete or other materials, so as to make the amount of radiation sustained by residents living nearby less than 0.01 mSv a year after the construction is completed, according to the guidelines.

The reuse is aimed to cut the amount of radioactive soil from Fukushima disaster to be shipped to other prefectures for final disposal, according to the ministry.

The decision was made despite public concerns that contaminated materials would still leach out as roads or other public works in which the tainted soil is used might decay or collapse during earthquakes, floods or other national disasters or fail over time.

Earlier estimates by a working group of the ministry showed that it would take as long as 170 years before the soil’s radiation levels drop to legal safety standards, while public works such as roads are often durable for just 70 years.

Under the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors, the safety standards for reusing materials generated from the Fukushima decontamination work are less than 100 becquerels of radioactive cesium per kilogram.

http://www.shanghaidaily.com/article/article_xinhua.aspx?id=330465

June 30, 2016 Posted by | Fukushima 2016 | , , , | Leave a comment